thanks. Just to make sure, while you said that your TSC was off on that laptop, the bootup log of yours suggests a working TSC:

Time: tsc clocksource has been installed.

and still your fl.c testcases produces the top output that you've reported in your first mail? If so then this could be a regression. Or did you turn off the tsc manually via notsc? (or was it with a different .config or on a different machine)? Please help us figure this out exactly, we dont want a real regression go unnoticed.

If you can reproduce that problem with a working TSC then please generate a second cfs-debug-info.sh snapshot _while_ your fl+l workload is running and send that to me (i'll reply back to it publicly). Thanks,